I think I have air getting into my fuel system from somewhere and I'm hoping you guys can help me narrow it down. I just had my truck sitting for a couple weeks and while it was in my shop I fixed a leaky fuel return line by replacing my O rings and it took quite a bit of extra torque to tighten up the nut that goes to the top of the injector. But I got it to where it didn't leak and she idled nice and smooth. While I was in there I drained the water seperator. A couple years ago I added a length of fuel line to the bottom of my water separator and a needle valve because sometimes the stock one didn't seat back in properly and it would let air in. Anyway, it idled just fine after those 2 maintenance tasks.

This morning I fire it up, drive 5 miles and stop 10 minutes. Try to start it again and it runs for 30 seconds, sputters and dies. I burped some air out of my fuel filter, got it to run down the street to a relative's place and began looking into it some more.

I can get it to start after holding in the schraeder valve on the fuel filter and burping air, however in order to keep it running I need to burp it every 10 seconds or so--and there's air coming out.

Not sure how much fuel I have in the tank, but feeling is it's low. Sender has never worked well since I've owned it. I'm going to add 5 gal before I get into it again tomorrow.

Any thoughts on the culprit?

 

If your running on low tanks you could be drawing air from a collapsed pick up in the tank. Fill the tanks and don't let it drop below 1/4. I had the same problem until I kept my tanks full and topped off regularly. That might not be the problem but it's an easy way to eliminate one possibility

 

I'd guess your low pressure fuel pump may be at fault; it's got a built-in check-valve, and if that goes, you might see leakdown like that.

No matter what, that's some /bad/ leakdown; usually it takes hours to leak to that point.

One easy solution is to just install a check-valve on the intake side of the fuel filter/separator... It solved my problem entirely.

 

Problem keeping it running means it is probably not a drain-back-lift-pump issue.

I like the fill-the-tank test. If the problem goes away you have an air leak in the pick-up tube.

Roy

 

Turns out it was low fuel. I love the easy fixes. Thanks for the help!

 

Well, that's great. But, you probably still have an issue. Unless you always want to run with a pretty full tank, you will want to fix the air leak in the pick-up tube (inside the fuel tank).

Roy

 

Yeah, I probably should check that out. I need to replace my front tank already, so once I can find one of those & I go in to replace that I'll look into the rear tank issue too.
Until then there's gonna be a 5gal can full of fuel in the back of the truck

 

where did you get the check valve and what size does it need to be?

 

I used one of these:
http://www.ebay.com/itm/Snowmobile-Primer-Bulb-1-4-to-5-16-Fuel-Line-NEW-/261319029267?pt=Snowmobile_Parts_Accessories&hash=item3cd7d3f213&vxp=mtrIt's a squeeze bulb which, by it's nature, has to have /two/ check valves inside it.
Plus it provides you a convenient primer, if you, say, drain your filter.
You can also tell if you have air in the line very easily -- if the bulb is squishy, you've got air. If it's hard, you don't... at least, as long as your fuel system is together.

When I got it, I expected to need to use the primer feature quite a bit, but it worked far better than expected, and I've only used it a couple of times(while working on the truck).